Muhammad bin Ubaydullah (may Allah have mercy on him) reports that Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him) said: "On the day of the Battle of Badr I killed Sa'id bin al-As and took his sword, and his sword was named Dhu al-Kutayfah." And he said: "My brother Umayr had also been killed. So I brought the sword to the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) said: 'Go and put this sword into the collected spoils.' So I went back, and what was in my heart over the killing of my brother and the taking of my sword, none but Allah knows. I had stayed only a little while when Surah al-Anfal was revealed, and the Messenger of Allah (peace and blessings be upon him) called me and said: 'Go and take your sword.'"